Convert everything in the Sky API from degrees to radians.

sky/examples/game/lib/transform_node.dart

 part of sprites;
 
 double degrees2radians(double degrees) => degrees * Math.PI/180.8;
 
 double radians2degrees(double radians) => radians * 180.0/Math.PI;
 
 class TransformNode {
   Vector2 _position;
   double _rotation;
   
@@ skipping 105 matching lines @@
     prePaint(canvas);
     paint(canvas);
     visitChildren(canvas);
     postPaint(canvas);
   }
   
   void prePaint(PictureRecorder canvas) {
     canvas.save();
     
     canvas.translate(_position[0], _position[1]);
-    canvas.rotateDegrees(_rotation);
+    canvas.rotate(degrees2radians(_rotation));
     canvas.translate(-_width*_pivot[0], -_height*_pivot[1]);
     
     // TODO: Use transformation matrix instead of individual calls
 //    List<double> matrix = [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0];
 //    this.transformMatrix.copyIntoArray(matrix);
 //    canvas.concat(matrix);
   }
   
   void paint(PictureRecorder canvas) {
     
   }
  
   void visitChildren(PictureRecorder canvas) {
     children.forEach((child) => child.visit(canvas));
   }
   
   void postPaint(PictureRecorder canvas) {
     canvas.restore();
   }
 
   void update(double dt) {
 
   }
-}
+}